Let us look at the Apostle's words more closely: he speaks of a work of faith; to take it exactly, of something which faith has done. Faith is a conviction with regard to things unseen, that makes them present and real. Faith in God as revealed in Christ, and in His death for sin, makes reconciliation real; it gives the believer peace with God. But it is not shut up in the realm of things inward and unseen. If it were, a man might say what he pleased about it, and there would be no check upon his words. Wherever it exists, it works; he who is interested can see what it has done. Apparently the Apostle has some particular work of faith in his mind in this passage; some thing which the Thessalonians had actually done, because they believed but what it is we cannot tell. Certainly not faith itself; certainly not love, as some think, referring to Gal. v. 6; if a conjecture may be hazarded, possibly some act of courage or fidelity under persecution, similar to those adduced in Heb. xi. That famous chapter contains a catalogue of the works which faith wrought; and serves as a commentary, therefore, on this expression. Surely we ought to notice that the great Apostle, whose name has been the strength and shield of all who preach justification by faith alone, the very first time he mentions this grace in his epistles, mentions it as a power which leaves its witness in work.
It is so, also, with love: "we remember," he writes, "your labour of love." The difference between ἔργον (work) and κόπος (labour) is that between effect and effort. The Apostle recalls something which the faith of the Thessalonians did; he recalls also the wearisome toil in which their love spent itself. Love is not so capable of abuse in religion, or, at least, it has not been so rankly abused, as faith. Men are much more apt to demand the proof of it. It has an inward side as much as faith, but it is not an emotion which exhausts itself in its own transports. Merely as emotion, indeed, it is apt to be undervalued. In the Church of to-day emotion needs rather to be stimulated than repressed. The passion of the New Testament startles us when we chance to feel it. For one man among us who is using up the powers of his soul in barren ecstasies, there are thousands who have never been moved by Christ's love to a single tear or a single heart throb. They must learn to love before they can labour. They must be kindled by that fire which burned in Christ's heart, and which He came to cast upon the earth, before they can do anything in His service. But if the love of Christ has really met that answer in love for which it waits, the time for service has come. Love in the Christian will attest itself as it attested itself in Christ. It will prescribe and point out the path of labour. The word employed in this passage is one often used by the Apostle to describe his own laborious life. Love set him, and will set every one in whose heart it truly burns, upon incessant, unwearied efforts for others' good. Paul was ready to spend and be spent at its bidding, however small the result might be. He toiled with his hands, he toiled with his brain, he toiled with his ardent, eager, passionate heart, he toiled in his continual intercessions with God, and all these toils made up his _labour_ of love. "A labour of love," in current language, is a piece of work done so willingly that no payment is expected for it. But a labour of love is not what the Apostle is speaking of; it is _laboriousness_, as love's characteristic. Let Christian men and women ask themselves whether their love can be so characterised. We have all been tired in our time, one may presume; we have toiled in business, or in some ambitious course, or in the perfecting of some accomplishment, or even in the mastery of some game or the pursuit of some amusement, till we were utterly wearied: how many of us have so toiled in love? How many of us have been wearied and worn with some labour to which we set ourselves for God's sake? This is what the Apostle has in view in this passage; and, strange as it may appear, it is one of the things for which he gives God thanks. But is he not right? Is it not a thing to evoke gratitude and joy, that God counts us worthy to be fellow-labourers with Him in the manifold works which love imposes?